US3695790A - Housing sealing means for rotary engines - Google Patents

Abstract

A means of sealing two abutting portions of an engine housing at a location where the available space for sealing means is restricted, by providing a generally annular thin plate having perforations for coolant flow and having an elastomeric gasket applied to each of the inner and outer peripheral edges of the plate, which is positioned in a congruent recess in one of the two abutting housing portions.

Description

United States Patent [15] 3,695,790 Jones [4 Oct. 3, 1972 FOR 3,196,849 7/1965 Paschke ..123/8.45

ROTARY ENGINES [72] Inventor: Charles Jones, 208 Forest Drive, Exa'mner wiuiam Freeh Hillsdale, NJ. 07642 Filed: May 24, 1971 Appl. No.: 146,051

US. Cl ..418/83, 418/ 149 Int. Cl. ..F0lc 21/06, FOlc 19/00 Field of Search ..418/83, 149, 142; 277/198,

[56] References Cited UNITED STATES PATENTS 3,575,538 4/1971 Berkowitz ..418/83 Assistant Examiner-Leonard Smith Att0meyRaymond P. Wallace and Victor D. Behn ABSTRACT A means of sealing two abutting portions of an engine housing at a location where the available space for sealing means is restricted, by providing a generally annular thin plate having perforations for coolant flow and having an elastomeric gasket applied to each of the inner and outer peripheral edges of the plate, which is positioned in a congruent recess in one of the two abutting housing portions.

5 Claims, 7 Drawing Figures minnows 2 3,695,790 SHEET 1 OF 2 I W PRIOR am" I INVENTOR. i 3a BY 6770/ /25 Jones mmmnma m2 3,695, 790

INVENTOR. Jones AGENT BY :u E R PWJML BACKGROUND OF THE INVENTION This invention relates to rotary internal combustion engines, and more particularly to such engines havinga peripheral housing closed by a pair of end walls, the peripheral housing and end walls having intercommunicating cavities comprising a jacket for the flow of liquid coolant.

In rotary engines of the trochoidal type the peripheral housing is the hardest portion to cool adequately because it is of limited axial extent and therefore has only a small inner surface for heat rejection from the combustion zone. For liquid-cooled engines the peripheral housing is a double-walled structure, the inner and outer walls being spaced apart by'rib members defining passages therebetween for the flow of the coolant. The end walls are hollow structures having coolant passages with apertures around the periphery of each end wall communicating with the passages through the peripheral housing. The coolant path is normally through the passages of one end wall, through the passages of the peripheral housing, and then into the other end wall. The flow path may change direction in the end walls and pass back and forth several times through alternating groups of passages in the peripheral housing.

In any case, the parallel end walls are assembled against the edges of the peripheral housing in tight relationship with the coolant apertures of the end walls aligned with those of the peripheral housing. For the purpose of preventing leakage of the coolant into the operating chambers of the engine or to the environment, it is necessary that sealing means be provided around the endfaces of the peripheral housing on both sides of the coolant passages, that is both radially inward and radially outward of the passages. It has been the prior art practice that the inner and outer wall portions of the peripheral housing should be thick enough to have a groove cut into the end edge thereof, withan elastomeric gasket positioned therein and compressed by the adjacent face of the end wall.

It is particularly undesirable to have the inner wall portion of the peripheral housing thick enough to hold such a gasket groove, since a thick wall would impair the efficacy of the coolant. It has, therefore, been the practice to reduce the inner wall thickness in the zone between a pair of thicker end portions left for the groove, but this is also unsatisfactory because such an expedient makes die-casting or permanent mold casting of the peripheral housing impossible, and has resulted in a slow and expensive coring procedure to produce the castings.

In U. S. Pat. No. 3,575,538, that particular aspect of the problem was solved by making only a portion of a groove in the circumferential edge of the inner wall as a locator for an O-ring gasket, and then holding the gasket to that position by a metal ring. The metal ring is so designed and dimensioned that coolant can flow around it, so that it does not constitute a thickening of the wall at that location, but it does nevertheless partially occlude the flow through the coolant passages. An additional difficulty is found at assembly, when a very thin O-ring of considerable length must be fitted into such a loosely formed site and remain in place while the side wall is bolted into position to compress the gasket.

SUMMARY The present invention overcomes the limitations of the prior art, requiring neither a thick wall nor a cumbersome coring procedure, nor yet the difficulty of handling and assembling long unsupported O-rings. The invention provides sealing at both the inner and outer wall portions of the peripheral housing by means of a thin annular plate, having holes therethrough congruent with the flow passages, and having an O-ring gasket attached to each of itsinner and outer circumferential edges, whereby the gasket assembly can be handled as a'unit and has sufficient stifi'ness to locate it merely be setting it in place. The edges of the inner and outer wall portions of the housing .aregiven a cut at the corners adjacent to the coolant passages, of sufficient depth .to contain the thickness of the metal portion of the gasket assembly. The assembly is disposed in the channel thus formed and the end walls bolted in place, compressing the O-rings which have a diameter in the relaxed condition substantially greater than the thickness of the annular plate.

It is, therefore, an object of this invention to provide housing sealing means for rotary engines.

It is another object to provide a rotary engine housing which can be cast in a permanent mold or a die.

A further object is to provide housing sealing means wherein a gasket assembly can be readily handled as a unit and rapidly installed.

Other objects and advantages will be understood on reading the following specification with reference to the annexeddrawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a semischematic vertical cross-section on the axial plane of a rotary engine of the prior art;

FIG. 2 is a fragmentary view taken on line 2-2 of FIG. .6, similar to a portion of FIG. 1, showing the invention in operative installation;

FIG. 3 is an enlarged view of the portion of FIG. 2 enclosed within circle A;

FIG. 4 is a section of the sealing means, taken on line 4-4 of FIG. 5;

FIG. 5 is a fragmentary side view .of the sealing means;

FIG. 6 is a partial view taken on line 6-6 of FIG. 2; and

FIG. 7 is a view similar to FIG. 4' of another embodiment of the gasket assembly.

DESCRIPTION OF THE PREFERRED EMBODIMENTS ing a sealing member 19 at each of its apexes which sweeps the epitrochoidal surface in sealing relationship. In the liquid-cooled engine shown, each of the end walls 14 is provided with internal passages 21 for the flow of coolant. The peripheral housing 12 is of doublewalled construction, having an inner wall portion 22 and an outer wall portion 23 spaced apart therefrom by ribs 24 which define coolant passages 26 (better shown in FIG. 6) through the peripheral housing in a direction generally parallel to the axial dimension of the engine.

An inlet and outlet (not shown) are provided in the end walls, and water or other liquid coolant flows through the passages 21 in one end wall, through passages 26 of the peripheral housing as shown by the arrows, and into the passages 21 of the other end wall, from which it is discharged. The flow path of the coolant may be directed in a predetermined pattern by the positioning of the various passages.

The inner wall portion 22 and the outer wall portion 23 of the peripheral housing as shown in FIG. 1 have circumferential grooves cut into their end faces, in which grooves are respectively positioned ()- rings 27 and 28 or other suitable gaskets. When the engine is as sembled with the end walls against the end faces of the peripheral housing the gaskets are compressed in their grooves and prevent leakage of the coolant, either to the interior of the engine or to the environment.

It will be apparent that the inner wall 22 which is exposed to combustion is an area from which heat must be rapidly removed and which must therefore be effectively cooled. For this reason the inner wall has in prior art engines been made thinner in its center portion 29 between the end portions which have to be thick enough to provide a gasket groove, the inner wall therefore tapering down toward the center portion from the heavy end portions. To make this center portion thinner requires a difficult and expensive coring procedure in casting the peripheral housing, and at best still leaves a considerable thickness of metal at the end faces, since the slope of the tapers must be fairly long for structural reasons and good casting procedure.

The present invention overcomes this limitation of the prior art by making both the inner and outer walls of the peripheral housing thin throughout, with an improved means of positioning and retaining the gaskets. Although it is of less importance to make the outer wall portion thin as far as cooling action is concerned, nevertheless the thick outer wall of the prior art, which had a gasket groove, used more metal and had more machining than in the present invention, which is therefore less expensive to manufacture.

. This invention also results in cost saving at assembly, since the prior art engine required handling and positioning of very flimsy, long O-rings, with the added difficulty of retaining them in their grooves until the side walls could be bolted on. The present device provides a gasket assembly comprising a generally annular plate having elastomeric double gaskets attached to the edges thereof, which is rigid enough to be handled readily as a unit and which can be simply laid in place before bolting on the side wall.

FIG. 2 is an enlarged section similar to the bottom portion of FIG. 1, showing the gasket assembly 31 in place. The inner and outer wall portions 22a and 23a of the peripheral housing are made thin throughout, that is, of less thickness than would be required to provide gasket grooves in their end faces. At each of the end faces of the wall portions 22a and 23a a circumferential shoulder 32 (better shown in FIG. 3) is cut into the wall on the side facing the coolant passages 26 between ribs 24. The edges of ribs 24 extend nearly to the end face of the peripheral housing, but are set far enough back not to interfere with making such a cut.

The gasket assembly 31 comprises a generally annular plate member 33 which is congruent with the profile of the peripheral housing. Apertures 34 are punched or machined through the annular plate, separated by ribs 36, the sizing and spacing of apertures 34 and ribs 36 being congruent with coolant passages 26 of the housing and housing ribs 24, respectively. As shown in FIGS. 3 and 4, the inner and outer edges of plate 33 are provided with a concave groove, which may be either a radius or a V-groove as may be convenient. A deformable gasket ring 37, which may be an O-ring or other suitable elastomeric material, is bonded to each of the grooved edges by means of an adhesive 38, or vulcanized thereto or otherwise attached. This procedure results in the generally annular gasket assembly 31 which may be handled as a unit. An arcuate portion of such a gasket assembly is shown in FIG. 5.

FIG. 6 shows a gasket assembly 31 positioned in its channel in one end of the peripheral housing, before bolting on the associated end wall 14. FIG. 3 shows a fragmentary view of the gasket in place after applying the end wall. The shoulder 32 has been cut just sufficiently deep in the axial direction to take the thickness of plate 33 of the gasket assembly with a few thousandths clearance, so that the end wall 14 does not ride on plate 33 but abuts on the end face of the peripheral housing. Gasket rings 37 have a diameter in the relaxed state substantially greater than the thickness of plate 33, so that rings 37 are compressed against shoulder 32 to form a seal when end wall 14 is applied.

In FIG. 7 there is shown another embodiment 31a of the gasket assembly. In this embodiment the inner and outer peripheral edges of plate 33a are stepped on each side to produce a thin flange 39. A molded elastomeric gasket 37a of generally horseshoe cross-section is snapped over the flange, with the wings 41 of the gasket lying in the steps of the flange substantially flush with the surface of the plate 33a. The body of the gasket 370 has a cross-sectional diameter greater than the thickness of the plate, and a hollow center so that it will compress against shoulder 32 as in the previously described embodiment. With gasket 31a it is unnecessary to bond the elastomeric material to the metal, it being held by friction and by its own tension, and thus it is easier to replace gaskets 37a if it should become necessary. Either plate 33 or 33a may be machined, but preferably is conveniently and inexpensively produced by stamping.

The coolant passages 26 in the peripheral housing may be of various sizes and spacing, according to the cooling requirements around the housing, but since the apertures 34 and ribs 36 of either plate 33 or 33a are congruent with the coolant passages there is no obstruction of flow.

What is claimed is:

1. In a rotary internal combustion engine having a pair of end walls having coolant passages therein, the

end walls being spaced apart by a generally annular peripheral housing having double circumferential walls spaced apart by ribs defining coolant passages therethrough in communication with the coolant passages of the end walls, the improvement comprising: a. each of the peripheral housing walls having a circumferential shoulder at each of its edges on the side adjacent to the coolant passages, the two shoulders of the opposed housing walls defining a generally annular channel of shallow depth in each end of the peripheral housing; a gasket assembly disposed in each of the channels;

c. the gasket assembly comprising a generally annular plate having apertures therethrough congruent with the coolant passages of the peripheral housing, and a continuous elastomeric gasket attached to and surrounding each edge of the generally annular plate.

2. The combination recited in claim 1, wherein each of the generally annular channels has an axial depth slightly greater than the thickness of the generally annular plate so that the end walls abut the end faces of the peripheral housing, and the elastomeric gaskets have a cross-sectional diameter greater than the thickness of the plate, so that they are compressed by the end walls.

3. The combination recited in claim 2, wherein the generally annular plate has a concave groove in each of its inner and outer edges, and the elastomeric gaskets are bonded to the grooved edges, so that the plate and the gaskets comprise a unitary assembly.

4. The combination recited in claim 2, wherein each of the elastomeric gaskets has a generally horseshoe cross-section with a groove between the ends of the horseshoe shape, the groove embracing the edge of the generally annular plate.

5. The combination recited in claim 4, wherein the generally annular plate has a circumferential flange extending from each of its inner and outer edges, the flange being thinner than the remainder of the plate, the groove of the gasket embracing the flange and the ends of the horseshoe section lying substantially flush with the surface of the plate on each side.

. I I UNITEIl STATES PATENT. OFFICE CERTIFICATE OF CORRECTION Patent No. 3, 95,790 Dated October 3, 1972 Intentofls) Charles Jones It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

7 On the cover sheet following item (72 insert the following:

(73) Assignee: Curtiss-Wr'ight Corporation-- Signed and sealed this 17th day of April .1973.

(SEAL) Attest:

r EDWARD M.FLETCHER,'JR.

ROBERT GOTTSCI-IALK Attesting Officer Commissioner of Patents F ORM PO-1050 (10-69) USCOMM-DC 60376-P69 1.5, GOVERNMENT PRINTING OFFICE I969 0-366-334,'

Claims (5)

1. In a rotary internal combustion engine having a pair of end walls having coolant passages therein, the end walls being spaced apart by a generally annular peripheral housing having double circumferential walls spaced apart by ribs defining coolant passages therethrough in communication with the coolant passages of the end walls, the improvement comprising: a. each of the peripheral housing walls having a circumferential shoulder at each of its edges on the side adjacent to the coolant passages, the two shoulders of the opposed housing walls defining a generally annular channel of shallow depth in each end of the peripheral housing; b. a gasket assembly disposed in each of the channels; c. the gasket assembly comprising a generally annular plate having apertures therethrough congruent with the coolant passages of the peripheral housing, and a continuous elastomeric gasket attached to and surrounding each edge of the generally annular plate.

2. The combination recited in claim 1, wherein each of the generally annular channels has an axial depth slightly greater than the thickness of the generally annular plate so that the end walls abut the end faces of the peripheral housing, and the elastomeric gaskets have a cross-sectional diameter greater than the thickness of the plate, so that they are compressed by the end walls.

3. The combination recited in claim 2, wherein the generally annular plate has a concave groove in each of its inner and outer edges, and the elastomeric gaskets are bonded to the grooved edges, so that the plate and the gaskets comprise a unitary assembly.

4. The combination recited in claim 2, wherein each of the elastomeric gaskets has a generally horseshoe cross-section with a groove between the ends of the horseshoe shape, the groove embracing the edge of the generally annular plate.

5. The combination recited in claim 4, wherein the generally annular plate has a circumferential flange extending from each of its inner and outer edges, the flange being thinner than the remainder of the plate, the groove of the gasket embracing the flange and the ends of the horseshoe section lying substantially flush with the surface of the plate on each sidE.

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